Methods for Improving Fruit Production and Fruit Quality

ABSTRACT

Disclosed herein are methods for improving fruit production or fruit quality in fruit trees, such as decreasing cold damage, increasing fruit size, increasing fruit quality, and/or increasing fruit set. In some embodiments, the disclosed methods include methods of decreasing cold damage to a fruit tree including applying an effective amount of a composition including DL-β-aminobutyric acid to the fruit tree, thereby decreasing cold damage, for example as compared to a control. In other embodiments, the disclosed methods include methods of increasing fruit size or fruit quality of fruit from a fruit tree, including applying an effective amount of a composition including prohexadione-calcium to the fruit tree after anthesis, thereby increasing fruit size or fruit quality, for example as compared to a control. In further embodiments, the disclosed methods include methods of increasing fruit size of fruit from a fruit tree or increasing fruit set of a fruit tree including applying an effective amount of a composition including 4-chlorophenoxyacetic acid to the fruit tree, thereby increasing fruit size or fruit set, for example as compared to a control.

CROSS REFERENCE TO RELATED APPLICATIONS

This claims the benefit of U.S. Provisional Application No. 61/334,419,filed May 13, 2010, U.S. Provisional Application No. 61/334,434, filedMay 13, 2010, and U.S. Provisional Application No. 61/352,531, filedJun. 8, 2010, each of which is incorporated herein by reference in theirentirety.

ACKNOWLEDGMENT OF GOVERNMENT SUPPORT

This invention was made with government support under award number2010-31100-06053 awarded by the United States Department of Agriculture.The government has certain rights in the invention.

FIELD

This disclosure relates to methods for improving aspects of fruitproduction and fruit quality of fruit trees, particularly utilizingplant growth regulators or a non-peptide amino acid.

BACKGROUND

There has been a recent worldwide increase in cherry production, with2009 crop production reaching two million metric tons (World SweetCherry Review, Belrose, Inc., Pullman, Wash., 2009). Factors such asfluctuating winter temperatures, spring frosts, rain-induced fruitcracking, and bird losses make cherry production challenging. Similarchallenges are present in other fruit crops, including plum, peach,nectarine, apple, and pear crops. Thus, there is a need for methods toimprove fruit production and fruit quality.

SUMMARY

Disclosed herein are methods for improving fruit production and/or fruitquality in fruit trees, such as decreasing cold damage, increasing fruitsize, increasing fruit quality, and/or increasing fruit set.

In some embodiments, the disclosed methods include methods of decreasingcold damage to a fruit tree including applying an effective amount of acomposition including DL-β-aminobutyric acid (BABA) to the fruit tree,thereby decreasing cold damage, for example as compared to a control.

In other embodiments, the disclosed methods include methods ofincreasing fruit size or fruit quality of fruit from a fruit tree,including applying an effective amount of a composition includingprohexadione-calcium (PCa) to the fruit tree after anthesis, therebyincreasing fruit size or fruit quality, for example as compared to acontrol. In some embodiments, the disclosed methods include applying aneffective amount of a composition including PCa and one or moregibberellins (such as gibberellin A3 (GA₃), gibberellin A4 (GA₄),gibberellin A7 (GA₇), or a combination of two or more thereof) to thefruit tree after anthesis. In particular examples, the composition (suchas a composition including PCa or a composition including PCa and one ormore GA) is applied to the tree at about 20 to 45 days after anthesis.

In further embodiments, the disclosed methods include methods ofincreasing fruit size of fruit from a fruit tree or increasing fruit setof a fruit tree including applying an effective amount of a compositionincluding 4-chlorophenoxyacetic acid (CPA) to the fruit tree, therebyincreasing fruit size or fruit set, for example as compared to acontrol. In some examples, the composition is applied to the fruit treeduring flowering or post-bloom.

In some examples of the disclosed methods, the composition is applied toleaves, buds, flowers, or branches of the tree, or a combination of twoor more thereof, for example by spraying. In some examples, the fruittree is a stone fruit tree, such as a sweet cherry, tart cherry, plum,peach, nectarine, or apricot tree. In other examples, the fruit tree isa pome fruit tree, such as an apple, pear, quince, or loquat tree.

The foregoing and other features of the disclosure will become moreapparent from the following detailed description, which proceeds withreference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A-E is a series of graphs showing the effect of BABA on sweetcherry cv. ‘Bing’ at −3.5° C. and −4.5° C. FIG. 1A, flower fate (%flowers killed); FIG. 1B, fruit set; FIG. 1C, fruit size; FIG. 1D,average leaf area; FIG. 1E, leaf chlorophyll content index. Control,untreated; P1, BABA, 100 ppm; P2, BABA, 500 ppm.

FIG. 2 is a series of panels showing flower hardiness of ‘Fuji’ apple atthe indicated flower bud developmental stages and temperatures inBABA-treated and untreated (control) branches. Branches were treatedwith BABA 5 days prior to cold temperature exposure.

FIG. 3 is a graph showing flower fate of the indicated sweet cherrycultivars after autumn application of BABA and following natural springfrost damage.

FIG. 4 is a pair of digital images showing pistil survival in sweetcherry cv. ‘Bing’ after autumn application of BABA and following springfrost damage. Left, control (untreated) branch; right, BABA-treatedbranch. Arrows indicate the pistil base. Pistils on the untreated branchwere discolored at the base, indicating that the pistil was dead.

FIG. 5 is a pair of digital images showing fruit set in plum cv.‘PP7524-7’ after application of BABA about 4-7 days prior to frost.Left, control (untreated) branch; right, BABA-treated branch.

FIG. 6 is a plot showing fruit size distribution in sweet cherry cv.‘Bing’ treated at 30 days after anthesis with PCa or the indicatedgibberellin isomers alone or in combination. The data show distributionof every fruit from replicate limbs, and 50-300 fruit/limb weremeasured. Size distribution is from <6 g to >10 g, from left to right inthe plot. GA1, gibberellin A1; GA3, gibberellin A3; GA4/7, mixture ofgibberellin A4 and gibberellin A7. Size distribution ranges fortreatments are as follows: GA1 ranges from 6 g to >10 g; PCa ranges from<6 g to 9 g; all others range from <6 g to >10 g.

FIG. 7 is a plot showing fruit color distribution in sweet cherry cv.‘Bing’ treated with PCa or gibberellin isomers alone or in combination,applied at 30 days after anthesis. Color distribution is from green toCtifl 7, from left to right of the plot. Color distribution ranges fortreatments are as follows: PCa+GA3+GA4/7, GA3, and GA1, each range fromCtifl 2 to Ctifl 5; PCa+GA4/7, GA3+GA4/7, and GA 4/7 each range fromCtifl 1 to Ctifl 5; PCa+GA3, PCa+GA1, and control each range from Ctifl1 toCtifl 4; PCa ranges from Ctifl 1 to Ctifl 6.

FIG. 8 is a graph showing current shoot length in sweet cherry cv.‘Bing’ treated with PCa or gibberellin isomers alone or in combination,applied at 30 days after anthesis. Data were collected after shootgrowth termination about three months following application. Valuesmarked with the same letter do not differ significantly (p>0.05).

FIG. 9 is a series of graphs showing mean fruit height (upper) and meanfruit equatorial diameter (lower) in sweet cherry cv. ‘Bing’ treatedwith PCa or PCa plus gibberellin, applied at 30 days (first spray, left)or 37 days (second spray, right) after anthesis (42 or 35 days beforeharvest, respectively).

FIG. 10 is a series of graphs showing average fruit weight, totalsoluble solid content, and firmness of cherries at harvest from sweetcherry cv. ‘Bing’ treated with PCa alone or in combination with GA3 orGA4/7, applied at day 30 (first spray, FS) or day 37 (second spray, SS)after anthesis (n=3). Values marked with the same letter do not differsignificantly (p>0.05).

FIG. 11 is a plot showing distribution of fruit size at harvest in sweetcherry cv. ‘Bing’ treated with PCa alone or in combination with GA3 orGA4/7, applied at day 30 (first spray, FS) or day 37 (second spray, SS)after anthesis (n=3). Size distribution is from <6 g to >10 g, from leftto right of the plot. Size distribution ranged from <6 g to >10 g forall treatments.

FIG. 12 is a plot showing the effect of PCa alone or in combination withgibberellins (GA3 or GA4/7) applied at early stage of fruit expansion of‘Bing’ cherry (30 days after anthesis) on the relationship between yieldof larger fruit (larger than 29.8 mm in diameter) and total yield on alltrees.

FIG. 13 is a plot showing cherry color distribution at harvest in sweetcherry cv. ‘Bing’ treated with PCa alone or in combination with GA3 orGA4/7, applied at day 30 (first spray, FS) or day 37 (second spray, SS)after anthesis. The graph shows percentage of cherries at each scale(green to Ctifl 7, from left to right of the plot). Size distributionranges for treatments are as follows: PCa+GA4/7 SS, PCa SS, PCa+GA4/7FS, and PCa+GA3 FS ranged from Ctifl 3 to Ctifl 6; PCa SS, PCa FS, andControl ranged from Ctifl 3 to Ctifl 7; and PCa+GA3 SS ranged from Ctifl2 to Ctifl 6.

FIG. 14 is a pair of graphs showing current shoot growth in sweet cherry‘Bing’ treated with PCa alone or in combination with GA3 or GA4/7,applied at day 30 (first spray, upper) or day 37 (second spray, lower)after anthesis.

FIG. 15 is a plot showing storability of fruit from sweet cherry cv.‘Bing’ treated with PCa alone or in combination with GA3 or GA_(4/7),applied at day 30 (first spray, FS) or day 37 (second spray, SS) afteranthesis. The plot shows the percentage of cherries at each of fourcategories: healthy, unblemished, and marketable (0); very slightdecayed or pitted, but marketable (1); around 50% decayed or pitted andunmarketable (2); and more than 50% decayed or pitted and unmarketable(3), from left to right of the plot. Distribution ranged from 0-3 forall treatments.

FIG. 16 is a series of graphs showing fruit firmness (left) or fruitwith green pedicel (right) after 30 days of storage. Fruit were fromsweet cherry cv. ‘Bing’ treated with PCa alone or in combination withGA3 or GA4/7, applied at day 30 (first spray, top) or day 37 (secondspray, bottom) after anthesis. The graphs show percentage of cherries attwo categories: healthy (O) or partly decayed or pitted (1) for fruitfirmness data. Error bars indicate standard deviation of the mean.

FIG. 17 is a diagram of an exemplary gibberellin biosynthetic pathwayfrom geranylgeranyl diphosphate (GGPP) and points of inhibition by PCa.Thick lines represent major activity and thin lines represent minoractivity of PCa, respectively.

FIG. 18 is a graph showing fruit set (% of available flowers) aftertreatment of ‘Bing’ sweet cherry at full bloom with the indicatedcompounds. The number following each compound name indicates the partsper million (ppm) applied. CPPU, N-2-chloro-4-pyridyl)-N′-phenylurea;Toplin, 6-(3-hydroxybenzylamino) purine; TDZ,N-phenyl-N′-(1,2,3-thiadiazol-5-yl) urea; BA, N6-benzyladenine; GA1,gibberellin A1; GA3, gibberellin A3; GA4/7, mixture of gibberellin A4and gibberellin A7; CPA, 4-chlorophenoxyacetic acid.

DETAILED DESCRIPTION I. Abbreviations

BABA: DL-β-aminobutyric acid

CPA (4-CPA): 4-chlorophenoxyacetic acid

GA: gibberellin

PCa prohexadione-calcium

ppm parts per million

II Terms

Unless otherwise noted, technical terms are used according toconventional usage. Unless otherwise explained, all technical andscientific terms used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this disclosurebelongs. The singular terms “a,” “an,” and “the” include pluralreferents unless context clearly indicates otherwise. Although methodsand materials similar or equivalent to those described herein can beused in the practice or testing of the present disclosure, suitablemethods and materials are described below.

All publications, patent applications, patents, and other referencesmentioned herein are incorporated by reference in their entirety. Incase of conflict, the present specification, including explanations ofterms, will control. In addition, the materials, methods, and examplesare illustrative only and not intended to be limiting.

In order to facilitate review of the various embodiments of thedisclosure, the following explanations of specific terms are provided:

DL-β-aminobutyric acid (BABA): Also known as DL-3-aminobutyric acid. Acompound having the following structure:

BABA is a non-protein amino acid known to induce resistance to bioticand abiotic stresses in plants (e.g., Jakab et al., Eur. J. PlantPathol. 107:29-37, 2001; Cohen, Plant Dis. 86:448-457, 2002).

Anthesis: The time of flowering of a plant, for example, the opening ofa flower bud. In some examples, anthesis is the time that a flower isaccessible to a pollinator (such as a bee).

Applying (to a tree): Contacting a tree or a portion of a tree (such asleaves, buds, flowers, branches, trunk, roots, or a combination of twoor more thereof) with an agent or composition.

4-chlorophenoxyacetic acid (CPA): Also known as parachlorophenoxyacetateor 4-chlorophenoxyacetate. A compound having the structure:

CPA is an auxin that is used in agriculture as an herbicide.

Control: A “control” refers to a sample or standard used for comparisonwith an experimental sample. In some embodiments, a control is anuntreated fruit tree or portion of a fruit tree (such as one or morebranches, buds, flowers, leaves, or a combination thereof). A control(such as an “untreated” control) may be a fruit tree or portion thereofto which no composition or treatment has been applied, or may be a fruittree or portion thereof to which an inert compound or carrier has beenapplied (such as water). In other examples, a control is a fruit tree orportion thereof which has been treated with a different composition forthe sake of comparison. In some embodiments, the control is a historicalcontrol or standard reference value or range of values (such as apreviously tested control sample, such as a group of untreated treesthat represent baseline or normal values, such as fruit size, fruitquality, fruit set, or cold damage).

Effective amount: An amount or dose sufficient to achieve a desiredeffect, such as decreasing cold damage, increasing fruit size,increasing fruit quality, and/or increasing fruit set of a fruit tree,for example as compared to a control.

Fruit set: An event where a flower's ovary is fertilized and will growinto fruit. The term fruit set includes the proportion or percentage offlowers which develop into a fruit. In some examples, fruit set includesinitial fruit set (proportion of flowers that form fruitlets) and/orfinal fruit set (proportion of flowers that become mature fruit and/orremain until commercial harvest). Fruit set is assessed by countingflowers in a limb or tree during anthesis (available flowers) and latercounting viable fruitlets or fruit from the same limb or tree.

Fruit tree: A tree bearing edible fruit, such as fruit for humanconsumption. In some examples, a fruit tree is a stone fruit tree. Astone fruit (or drupe) is a fruit with a fleshy outer part surrounding aone or a few seeds enclosed in a stony layer derived from the ovary wallof the flower. Exemplary stone fruit include sweet cherry (e.g., Prunusavium), tart (or sour) cherry (e.g., Prunus cerasus), plum (e.g., Prunusdomestica, Prunus salicina, or Prunus insititia), peach (e.g., Prunuspersica), nectarine (e.g., Prunus persica var. nucipersica), and apricot(e.g., Prunus armeniaca). In other examples, a fruit tree is a pomefruit tree. A pome is a fruit in which the seeds are protected by atough carpel wall and the entire fruit is embedded in a fleshyreceptacle. Exemplary parries include apple (e.g., Malus domestica),pear (e.g., Pyrus communis or Pyrus pyrifolia), quince (e.g., Cydoniaoblonga), and loquat (e.g., Eriobotiya japonica).

Gibberellin (GA): A family of more than one hundredtetracyclicditerpenes that regulate plant growth and development.Bioactive GAs are involved in several aspects of plant development, suchas seed germination, flower induction and fruit and seed development. Insome examples, GAs are tetracyclicditerpenoid carboxylic acids having a20-nor-ent-gibberellene skeleton, a carboxyl group on C-6, a lactonefunction between C-4 and C-10, and a hydroxyl or other functionality atC-3β. In some examples, gibberellins include gibberellin A1 (GA1),gibberellin A3 (GA3), gibberellin A4 (GA4), gibberellin A7 (GA7), or acombination of two or more thereof. For example, GA4/7 indicates amixture of GA4 and GA7. The structures of GA3, GA4 and GA7 are shownbelow.

Prohexadione-calcium (PCa): Also known as calcium3-oxido-4-propionyl-5-oxo-cyclohexene carboxylate. A compound having thestructure:

PCa is an inhibitor of GA biosynthesis.

III. Methods of Decreasing Cold Damage

Disclosed herein are methods of decreasing cold damage to a fruit tree.The methods include applying to the fruit tree (or a portion thereof) aneffective amount of a composition including DL-β-aminobutyric acid(BABA), thereby decreasing cold damage to the fruit tree as compared toa control. In some examples, the methods decrease cold damage to a fruittree that occurs when temperatures (such as air temperatures) are about5° C. or less (such as, but not limited to about 5° C., 4° C., 3° C., 2°C., 1° C., 0° C., −1° C., −2° C., −3° C., −4° C., −5° C., −6° C., −7°C., −8° C., −9° C., −10° C., −11° C., −12° C., −13° C., −14° C., −15°C., −16° C., −17° C., −18° C., −19° C., −20° C., −25° C., −30° C., orless). In other examples, the methods decrease damage to a fruit tree attemperatures of about 5° C. to −40° C. (for example, about −5° C. to−30° C., −10° C. to −20° C., 4° C. to −10° C., or 0° C. to −5° C.). Insome examples, the disclosed methods decrease cold damage to a fruittree when the tree is exposed to cold temperatures (for example, about0° C. or less) for at least about 10 minutes (such as, but not limitedto at least about 30 minutes or about 1, 2, 3, 4, 6, 8, 10, 12, 16, 18,20, 24, 36, 48, or more hours). One of skill in the art can identifytemperatures and lengths of exposure that are likely to cause colddamage based on the type of fruit tree, developmental stage of buds,flowers, or fruit, overall tree health, tree vigor, tree nutritionalstatus, and so on.

In some embodiments, the methods include applying the composition tofruit tree leaves, buds, flowers, branches, or a combination of two ormore thereof. In particular examples, the composition is applied to thetree by spraying, for example spraying with a solution including BABA.In some examples, the composition is applied (for example sprayed) onthe fruit tree or portion thereof until it runs off the tree (forexample, the leaves, buds, flowers, and/or branches). In other examples,the composition is applied (for example, sprayed) on the fruit tree orportion thereof at a rate of at least about 50 gallons/acre (forexample, about 75, 100, 125, 150, 175, 200, 225, 250, or more ga/acre).

In some examples, the methods include applying the composition includingBABA to the fruit tree or portion of the fruit tree (such as leaves,buds, flowers, branches, or a combination of two or more thereof) duringbud or flower development. In some examples, the composition includingBABA is applied to the fruit tree or portion thereof during autumn (forexample, after leaf drop), during bud development, during flowerdevelopment (for example prior to full bloom), or a combination of twoor more thereof. In other examples, the composition including BABA isapplied in the spring (for example during bud or flower development)prior to frost or freezing temperatures, such as about 1-10 days priorto freezing temperatures. For example, the composition including BABA isapplied about 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 days prior to occurrenceof freezing temperatures. In some examples, the methods include one ormore applications of the composition including BABA (such as 1, 2, 3, 4,5, or more applications).

In some embodiments, the disclosed methods include applying to a fruittree or a portion thereof a composition including about 50-750 ppm BABA(such as, but not limited to about 50-500 ppm, 100-300 ppm, 50-200 ppm,or 100-200 ppm). In some examples, the composition includes at least 50ppm BABA (for example, about 50, 100, 150, 200, 250, 300, 350, 400, 450,500, 550, 600, 650, 700, or 750 ppm). In a particular example, thecomposition includes about 100 ppm BABA. In another particular example,the composition includes about 500 ppm BABA.

Cold damage to a fruit tree can be assessed by methods known to one ofskill in the art, including but not limited to determining flowerskilled, fruit set, fruit size, pistil survival, leaf area, and/or leafchlorophyll content index. In some examples of the disclosed methods,decreasing cold damage includes decreasing flowers killed after exposureto cold temperature (for example, a temperature of about 0° C. or less),for example decreasing the percentage of flowers killed as compared to acontrol (such as an untreated or vehicle treated tree or population oftrees). For example, decreasing cold damage includes decreasing thepercentage of flowers killed on a fruit tree or a portion thereof by atleast about 10% (such as, but not limited to about 20%, 30%, 40%, 50%,60%, 70%, 80%, 90%, 95%, or even more) as compared to a control. Inother examples, decreasing cold damage includes having less than 90% offlowers killed (such as, but not limited to less than 80%, 70%, 60%,50%, 40%, 30%, 25%, 20%, 15%, 10%, or 5% of flowers killed) on a tree orportion of a tree after exposure to cold temperature (for example, atemperature of about 0° C. or less). One of skill in the art candetermine if a flower has been killed (for example, by visual assessmentfor the presence of discolored pistil tissues).

In other examples of the disclosed methods, decreasing cold damageincludes increasing fruit set after exposure to cold temperature (forexample, a temperature of about 0° C. or less), for example increasingthe percentage of flowers which develop into fruit as compared to acontrol (such as an untreated or vehicle treated tree or population oftrees). For example, decreasing cold damage includes increasing thepercentage of flowers which develop into fruit on a fruit tree or aportion thereof by at least about 10% (such as, but not limited to about25%, 50%, 75%, 1.5-fold, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, ormore) as compared to a control. In other examples, decreasing colddamage includes having a fruit set of more than about 30% (such as, butnot limited to about 40%, 50%, 60%, 70%, 80%, 90%, 95%, or more) on atree or a portion of a tree after exposure to cold temperature (forexample, a temperature of about 0° C. or less).

In further examples of the disclosed methods, decreasing cold damageincludes increasing fruit size after exposure to cold temperature (forexample, a temperature of about 0° C. or less), for example increasingthe weight, length, width, and/or diameter of fruit as compared to acontrol (such as an untreated or vehicle treated tree or population oftrees). For example, decreasing cold damage includes increasing at leastone measure of fruit size by at least about 10% (such as, but notlimited to about 25%, 50%, 75%, 1.5-fold, 2-fold, 3-fold, 4-fold,5-fold, 10-fold, or more) as compared to a control.

In some examples of the disclosed methods, decreasing cold damageincludes increasing pistil survival after exposure to cold temperature(for example, a temperature of about 0° C. or less), for exampleincreasing the percentage of surviving pistils as compared to a control(such as an untreated or vehicle treated tree or population of trees).For example, decreasing cold damage includes increasing pistil survivalon a fruit tree or a portion thereof by at least about 10% (such as, butnot limited to about 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, oreven more) as compared to a control. In some examples, pistil survivalis determined by visual examination of the pistil tissue (includingpistil, style, and/or ovaries/locules). The presence of brown or blacktissue on pistil tissue or a portion thereof indicates tissue death (forexample, killed by cold damage).

In other examples of the disclosed methods, decreasing cold damageincludes increasing leaf size after exposure to cold temperature (forexample, a temperature of about 0° C. or less), for example increasingleaf length, width, and/or area as compared to a control (such as anuntreated or vehicle treated tree or population of trees). For example,decreasing cold damage includes increasing at least one measure of leafsize by at least about 10% (such as, but not limited to about 25%, 50%,75%, 1.5-fold, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more) ascompared to a control.

In additional examples of the disclosed methods, decreasing cold damageincludes increasing leaf chlorophyll content after exposure to coldtemperature (for example, a temperature of about 0° C. or less), forexample increasing leaf chlorophyll content index as compared to acontrol (such as an untreated or vehicle treated tree or population oftrees). In other examples, decreasing cold damage includes increasingchlorophyll fluorescence after exposure to cold temperature (forexample, a temperature of about 0° C. or less), for example increasingchlorophyll fluorescence as compared to a control (such as an untreatedor vehicle treated tree or population of trees). For example, decreasingcold damage includes increasing at least one measure of leaf chlorophyllcontent by at least about 10% (such as, but not limited to about 25%,50%, 75%, 1.5-fold, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more) ascompared to a control.

For the purposes of determining cold damage to a fruit tree, one or moretrees or a portion of one or more trees can be used. Parameters thatreflect cold damage (for example, flowers killed, fruit set, pistilsurvival, fruit size, leaf size, and/or leaf chlorophyll content) can bedetermined using routine methods. The parameter can be assessed in thetreated tree (or portion thereof) and optionally in a control tree (orportion thereof) or an untreated portion of the treated tree. Theparameter in the treated tree can be compared to the same parameter inan untreated tree or other control (such as a standard value orreference value). In some examples, the increase or decrease in themeasured parameter is a significant (for example, statisticallysignificant) increase or decrease. A significant increase or decrease inthe parameter can be evaluated using statistical methods known in theart.

IV. Methods of Increasing Fruit Set, Fruit Size, and Fruit Quality

Disclosed herein are methods for increasing one or more aspects of fruitproduction by a fruit tree, including fruit set, fruit size, and fruitquality (such as one or more of fruit firmness, sweetness, color, totalsoluble content, and storability). In some embodiments, the methodsinclude applying a composition including one or more plant growthregulators to a fruit tree.

A. Prohexadione-Calcium

In some embodiments, the disclosed methods include increasing fruitsize, fruit quality, or a combination thereof of fruit from a fruittree. The methods include applying to the fruit tree (or a portionthereof) an effective amount of a composition including PCa or PCa andone or more gibberellins (such as GA1, GA3, GA4, GA7, or a combinationof two or more thereof). In particular examples, the methods includeapplying to the fruit tree an effective amount of a compositionincluding PCa and GA3 or a composition including PCa and a combinationof GA4 and GA7 (GA4/7). In some examples, GA4/7 includes a mixture ofabout 70:30 GA4: GA7.

In some embodiments, the methods include applying the composition tofruit tree leaves, buds, flowers, branches, or a combination of two ormore thereof. In particular examples, the composition is applied to thetree by spraying, for example spraying with a solution including PCa orPCa and one or more gibberellins. In some examples, the composition isapplied (for example, sprayed) on the fruit tree or portion thereofuntil it runs off the tree (for example, the leaves, buds, flowers,and/or branches). In other examples, the composition is applied (forexample, sprayed) on the fruit tree or portion thereof at a rate of atleast about 50 gallons/acre (for example, about 75, 100, 125, 150, 175,200, 225, 250, or more ga/acre). In some examples, the methods includeapplying the composition including PCa or PCa and one or moregibberellins to the fruit tree or portion of the fruit tree (such asleaves, buds, flowers, branches, or a combination of two or morethereof) during fruit development.

In some examples, the composition is applied to the fruit tree orportion thereof between about day 20 to day 40 after anthesis (such asabout day 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34,35, 36, 37, 38, 39, or 40 after anthesis). In a particular example, thecomposition including PCa or PCa and one or more gibberellins is appliedto the fruit tree at about day 30 after anthesis. In another particularexample, the composition including PCa or PCa and one or moregibberellins is applied to the fruit tree at about day 37 afteranthesis. One of skill in the art can identify when anthesis (fullflower opening) occurs. In some examples, anthesis is the time ofopening of a flower bud (for example, when a flower becomes accessibleto a pollinator). Anthesis is determined on a bud-by-bud basis. However,in some non-limiting examples, it is determined for a tree as a pointwhen a particular number or percentage of flower buds on the tree haveopened, for example, more than about 50% of flower buds opened (such as,but not limited to about 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or moreof flower buds opened). In one example, anthesis refers to full bloom ofa tree, for example, the time when all or substantially all flowers onthe tree have opened.

In other examples, the composition is applied to the fruit tree orportion thereof during stage II of fruit development. One of skill inthe art can identify the stage of fruit development for a particulartype of fruit. For example, stone fruit crops have three stages of fruitdevelopment: stage I, characterized by an increase in number and size ofseed and mesocarp cells; stage II, differentiation of the endocarp andpit hardening with little radial expansion; and stage III, expansion ofthe mesocarp from cell expansion (see, e.g., Westwood, Temperate-ZonePomology: Physiology and Culture, 3^(rd) ed., Timber Press, 2003). Insome examples, stage I lasts until the pit hardens (for example, testedby cutting through fruitlets), stage II last until a color change fromgreen to yellow, and stage III lasts until harvest.

In some examples, the methods include one or more applications of thecomposition including PCa or PCa and one or more gibberellins (such as1, 2, 3, 4, 5, or more applications).

In some embodiments, the disclosed methods include applying to a fruittree or a portion thereof a composition including about 50-300 mg/L PCa(such as, but not limited to about 100-300 mg/L, about 50-250 mg/L,about 100-200 mg/L, or about 150 mg/L). In a particular example, acomposition including about 150 mg/L PCa is applied to the fruit tree.In other embodiments, the disclosed methods include applying to a fruittree or a portion thereof a composition including about 50-300 mg/L PCa(such as, but not limited to about 100-300 mg/L, about 50-250 mg/L,about 100-200 mg/L, or about 150 mg/L) and about 10-50 mg/L (such as,but not limited to about 10-40 mg/L, about 10-30 mg/L, about 20-40 mg/L,or about 30 mg/L) of one or more gibberellins. In one particularexample, the methods include applying to a fruit tree a compositionincluding about 150 mg/L PCa and about 30 mg/L GA3. In anotherparticular example, the methods include applying to a fruit tree acomposition including about 150 mg/L and about 30 mg/L GA4/7 (such as,but not limited to 70:30 GA4:GA7).

Fruit size can be assessed by methods known to one of skill in the art,including but not limited to determining fruit weight, fruit length,fruit width, fruit diameter, or a combination of two or more thereof. Insome examples of the disclosed methods, increasing fruit size includesincreasing fruit weight (for example, average fruit weight) by at leastabout 5% (such as, but not limited to about 10%, 15%, 20%, 25%, 50%,75%, 1.5-fold, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more) ascompared to a control. In other examples, the percentage of fruit in aparticular weight range is increased by at least about 5% (such as, butnot limited to about 10%, 15%, 20%, 25%, 50%, 75%, 1.5-fold, 2-fold,3-fold, 4-fold, 5-fold, 10-fold, or more) as compared to a control. Oneof skill in the art can determine appropriate weight ranges for a givenfruit. For example, exemplary weight ranges for cherries are less than 6g, 6-7 g, 7-8 g, 8-9 g, 9-10 g, and greater than 10 g. In a particularexample, the percentage of cherries weighing greater than 10 g isincreased as compared to a control.

In other examples, increasing fruit size includes increasing one or moreof fruit length, fruit width, or fruit diameter (such as average length,width, and/or diameter) by at least about 5% (such as, but not limitedto about 10%, 15%, 20%, 25%, 50%, 75%, 1.5-fold, 2-fold, 3-fold, 4-fold,5-fold, 10-fold, or more) as compared to a control. In further examples,increasing fruit size includes increasing row size (for example, averagerow size) by at least 5% (such as, but not limited to about 10%, 15%,20%, 25%, 50%, 75%, 1.5-fold, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold,or more) as compared to a control. One of skill in the art can determinerow size by routine methods, for example, using a sizing chart or sizerrings.

Fruit quality can be assessed by methods known to one of skill in theart, including but not limited to determining fruit firmness, fruittotal soluble solid content, fruit acidity, fruit color, fruitstorability, fruit sensory attributes, or a combination of two or morethereof. In some examples of the disclosed methods, increasing fruitquality includes increasing fruit firmness (for example, average fruitfirmness) by at least about 5% (such as, but not limited to about 10%,15%, 20%, 25%, 50%, 75%, 1.5-fold, 2-fold, 3-fold, 4-fold, 5-fold,10-fold, or more) as compared to a control. Fruit firmness can bedetermined by methods known to one of skill in the art, for example,utilizing a fruit firmness tester (such as FirmTech 2, BioWorks, Inc.,Wamego, Kans.) or the Magness-Taylor firmness test.

In further examples, increasing fruit quality includes increasing fruitjuice total soluble solid content, pH, and/or titratable acidity by atleast about 5% (such as, but not limited to about 10%, 15%, 20%, 25%,50%, 75%, 1.5-fold, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more) ascompared to a control. One of skill in the art can determine solublesolids, for example utilizing a refractometer. Likewise, one of skill inthe art can determine juice pH and titratable acidity, for exampleutilizing a pH meter or titrator.

In still further examples, increasing fruit quality includes increasingfruit color, for example by increasing the percentage of fruit at aparticular color by at least about 5% (such as, but not limited to about10%, 15%, 20%, 25%, 50%, 75%, 1.5-fold, 2-fold, 3-fold, 4-fold, 5-fold,10-fold, or more) as compared to a control. Methods for assessing fruitcolor are known to one of skill in the art. In some examples, colorsorting is carried out with color comparators developed by CTIFL (CentreTechnique Interprofessionnel des Fruit et Legumes), which categorizescolor into eight levels from green, CTIFL 1 to CTIFL 7.

In other examples, increasing fruit quality includes increasing fruitstorability (for example, shelf life) by at least about 5% (such as, butnot limited to about 10%, 15%, 20%, 25%, 50%, 75%, 1.5-fold, 2-fold,3-fold, 4-fold, 5-fold, 10-fold, or more) as compared to a control. Insome examples, fruit storability is assessed by rating fruit by thedegree of decay following a period of storage (for example, storage atroom temperature or under refrigeration, such as about 4° C.). In someexamples, fruit is stored for at least 3 days (such as, but not limitedto at least 5, 7, 10, 14, 21, 28, 30, 45, 60, or more days). In oneexample, fruit is rated according to degree of decay and surface pittinginto at least four groups: 0, healthy and free of defects; 1, partialdecay or pitting; 2, around 50% decay or pitting; and 4, more than 50%decay and pitting. In some examples, the disclosed methods increase thepercentage of fruit in categories 0 and/or 1 after storage, as comparedto a control. In further examples, fruit storability is assessed bymeasuring fruit firmness and/or other fruit quality attributes, asdescribed herein. In some examples, the disclosed methods increase thefirmness of fruit after storage, as compared to a control. In furtherexamples, the disclosed methods increase total soluble solid content,pH, titratable acidity, fruit color, sensory attributes, or acombination of two or more thereof after storage, as compared to acontrol. In additional examples, fruit storability is assessed bydetermining the percentage of fruit with a particular visualcharacteristic, for example fruit with a green pedicel, for cherries. Insome examples, the disclosed methods increase the percentage of cherrieswith a green pedicel after storage as compared to a control.

In further examples, fruit quality includes sensory attributes (forexample, overall appearance, firmness, sweetness, tartness, flavor, andoverall acceptance). Sensory attributes are expressed on a relativescale (for example, from 0 to 10, where 0 represents the worst and 10represents the best) as evaluated by one or more individuals. In someembodiments, increasing fruit quality includes increasing a rating ofone or more sensory attributes (for example, increasing the rating by atleast one numerical value or step) as compared to a control. In someexamples, one or more sensory attributes are increased after storage,for example, as compared to a control.

For the purposes of determining fruit size or fruit quality, fruit fromone or more trees or a portion of one or more trees can be used (forexample fruit from a treated tree or portion thereof and optionallyfruit from a control tree or portion thereof). Parameters that reflectfruit size (such as fruit weight, fruit length, fruit width, and/orfruit diameter) or fruit quality (such as fruit firmness, fruit totalsoluble solid content, fruit color, fruit storability, and/or fruitsensory attributes) can be determined using routine methods. Theparameter can be assessed in fruit from the treated tree (or portionthereof) and optionally in from fruit from a control tree (or portionthereof) or an untreated portion of the treated tree. The parameterdetermined for fruit from the treated tree can be compared to the sameparameter in fruit from an untreated tree or other control (such as astandard value or reference value). In some examples, the increase ordecrease in the measured parameter is a significant (for example,statistically significant) increase or decrease. A significant increaseor decrease in the parameter can be evaluated using statistical methodsknown in the art.

B. 4-Chlorophenaxyacetic Acid

In some embodiments, the disclosed methods include increasing fruitsize, fruit set, or a combination thereof of a fruit tree. The methodsinclude applying to the fruit tree (or a portion thereof) an effectiveamount of a composition including CPA.

In some embodiments, the methods include applying the composition tofruit tree leaves, buds, flowers, branches, or a combination of two ormore thereof. In particular examples, the composition is applied to thetree by spraying, for example spraying with a solution including CPA. Insome examples, the composition is applied (for example, sprayed) on thefruit tree or portion thereof until it runs off the tree (for example,the leaves, buds, flowers, and/or branches). In other examples, thecomposition is applied (for example, sprayed) on the fruit tree orportion thereof at a rate of at least about 50 gallons/acre (forexample, about 75, 100, 125, 150, 175, 200, 225, 250, or more ga/acre).In some examples, the methods include applying the composition includingCPA to the fruit tree or portion of the fruit tree (such as leaves,buds, flowers, branches, or a combination of two or more thereof) duringflowering (including but not limited to first opening, full bloom, or acombination thereof) or post-bloom. In a particular example, thecomposition including CPA is applied to the fruit tree or portionthereof at full bloom. In other examples, the composition including CPAis applied to the fruit tree when there are open flowers on the tree. Ina further example, the composition including CPA is applied to the fruittree or portion thereof about 1-10 days post-bloom (such as about 1, 2,3, 4, 5, 6, 7, 8, 9, or 10 days post-bloom). One of skill in the art canidentify when flowering occurs. In some examples, flowering of a treeincludes at least about 10% open flowers (such as, but not limited toabout 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or more openflowers). In some examples, the methods include one or more applicationsof the composition including CPA (such as 1, 2, 3, 4, 5, or moreapplications). In one particular example, the composition including CPAis applied to a fruit tree or portion thereof at about 50% bloom and atfull bloom.

In some embodiments, the disclosed methods include applying to a fruittree or a portion thereof a composition including about 10-100 mg/L CPA(such as, but not limited to about 10-75 mg/L, about 25-50 mg/L, about10-50 mg/L, or about 30 mg/L). In a particular example, a compositionincluding about 30 mg/L CPA is applied to the fruit tree. In otherexamples, a composition including about 10 mg/L CPA is applied to thefruit tree. In still further examples, a composition including about 100mg/L CPA is applied to the fruit tree.

Fruit size can be assessed by methods known to one of skill in the art,including but not limited to determining fruit weight, fruit length,fruit width, fruit diameter, or a combination of two or more thereof. Insome examples of the disclosed methods, increasing fruit size includesincreasing fruit weight (for example, average fruit weight) by at leastabout 5% (such as, but not limited to about 10%, 25%, 50%, 75%,1.5-fold, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more) as comparedto a control. In other examples, the percentage of fruit in a particularweight range is increased by at least about 5% (such as, but not limitedto about 10%, 25%, 50%, 75%, 1.5-fold, 2-fold, 3-fold, 4-fold, 5-fold,10-fold, or more) as compared to a control. One of skill in the art candetermine appropriate weight ranges for a given fruit. For example,exemplary weight ranges for cherries are less than 6 g, 6-7 g, 7-8 g,8-9 g, 9-10 g, and greater than 10 g. In a particular example, thepercentage of cherries weighing greater than 10 g is increased ascompared to a control.

In other examples, increasing fruit size includes increasing one or moreof fruit length, fruit width, or fruit diameter (such as, but notlimited to average length, width, and/or diameter) by at least about 5%(such as, but not limited to about 10%, 25%, 50%, 75%, 1.5-fold, 2-fold,3-fold, 4-fold, 5-fold, 10-fold, or more) as compared to a control. Infurther examples, increasing fruit size includes increasing row size(for example, average row size) by at least 5% (such as, but not limitedto about 10%, 15%, 20%, 25%, 50%, 75%, 1.5-fold, 2-fold, 3-fold, 4-fold,5-fold, 10-fold, or more) as compared to a control. One of skill in theart can determine row size by routine methods, for example, using asizing chart or sizer rings.

Fruit set can be assessed by methods known to one of skill in the art.In some examples of the disclosed methods, increasing fruit set includesincreasing percentage of flowers developing into fruit by at least about5% (such as, but not limited to about 10%, 25%, 50%, 75%, 1.5-fold,2-fold, 3-fold, 4-fold, 5-fold, 10-fold, or more) as compared to acontrol. In some examples, fruit set includes initial fruit set (such aspercentage or proportion of flowers developing into fruitlets), finalfruit set (such as percentage or proportion of flowers developing intomature fruit), or a combination thereof. In some examples, fruit set isdetermined on one or more selected branches or limbs of one or moretrees. For example, fruit set can be assessed by counting total flowerson a representative tree limb and counting the number of fruit on thelimb at later time points, for example every week, or at harvest. Fruitset is expressed as fruit per available flowers.

For the purposes of determining fruit size or fruit set, one or moretrees or a portion of one or more trees can be used. Parameters thatreflect fruit size (for example, fruit weight, fruit length, fruitwidth, and/or fruit diameter) or fruit set (for example, percentage offlowers that start developing into fruit and/or percentage of flowersthat become mature fruit) can be determined using routine methods. Theparameter can be assessed in the treated tree (or portion thereof) andoptionally in a control tree (or portion thereof) or an untreatedportion of the treated tree. The parameter determined for the treatedtree can be compared to the same parameter in an untreated tree or othercontrol (such as a standard value or reference value). In some examples,the increase or decrease in the measured parameter is a significant (forexample, statistically significant) increase or decrease. A significantincrease or decrease in the parameter can be evaluated using statisticalmethods known in the art.

V. Fruit Trees

The methods disclosed herein can be used to improve aspects of fruitproduction and fruit quality in various fruit trees. In someembodiments, the fruit tree is a stone fruit tree, including, but notlimited to sweet cherry (e.g., Prunus avium), tart (“sour” or “pie”)cherry (e.g., Prunus cerasus), plum (e.g., Prunus domestica, Prunussalicina, or Prunus insititia), peach (e.g., Prunus persica), nectarine(e.g., Prunus persica var. nucipersica), or apricot (e.g., Prunusarmeniaca) tree. In particular examples, the fruit tree is a sweetcherry (Prunus avium) cultivar, such as ‘Bing,’ ‘Chelan,’ ‘Van,’‘Tieton,’ ‘PC 8011-3,’ ‘Regina,’ ‘Rainier,’ ‘Chinook,’ ‘Lambert,’‘Compact Lambert,’ ‘Corum,’ ‘Emperor Francis,' Gold,’ ‘Napoleon’ (alsoknown as ‘Royal Ann’ or ‘Queen Ann’), ‘Hedelfingen,’ ‘Hudson,’ ‘Sam,’‘Schmidt,’ ‘Stella,’ ‘Sweetheart,’ ‘UIster,’ ‘Vista,’ ‘Windsor,’ ‘Bada,’‘Sweet Ann,’ ‘Vega,’ ‘Black Republican,’ ‘Black Tartarian,’ ‘Cavalier,’‘Early Burlat,’ ‘Hardy Giant,’ ‘Kristin,’ ‘Summit,’ ‘Utah Giant,’‘Valera,’ ‘Venus,’ ‘Viscount,’ ‘Viva,’ ‘Vogue,’ ‘Lapins,’ ‘Attika,’‘Sunburst,’ or ‘Starkrimson.’ In other examples, the fruit tree is atart (sour) cherry (Prunus cerasus) cultivar, such as ‘Montmorency,’‘Meteor,’ ‘Northstar,’ ‘English Morello,’ ‘Kentish Red,’ ‘Amarelles,’‘Griottes,’ ‘Flemish,’ or ‘Schattenmorelle.’ In some examples, the fruittree is a plum (Prunus domestica, Prunus salicina, or Prunus insititia)cultivar, such as ‘PP 7524-7,’ ‘Reine Claude,’ ‘Imperial Gage,’ ‘Hand,’‘Yellow egg,’ ‘Golden drop,’ ‘Victoria,’ ‘Lombard,’ ‘Pond,’ ‘French,’‘Stanley,’ ‘Italian,’ ‘Blufre,’ ‘President,’ ‘Santa Rosa,’ ‘Burbank,’‘Shiro,’ ‘Beauty,’ ‘Gold,’ ‘Methley,’ ‘Hollywood,’ ‘Red Beaut,’ ‘OzarkPremier,’ ‘Friar,’ or ‘Simka.’ In further examples, the fruit tree is apeach (Prunus persica) cultivar, such as ‘Redhaven,’ ‘Glohaven,’ ‘RedGlobe,’ ‘Canadian Harmony,’ ‘Elberta’ (including ‘Early Elberta,’‘Fantastic Elberta,’ or ‘July Elberta’), ‘Veteran,’ ‘Reliance,’‘Harken,’ ‘Polly,’ ‘Ranger,’ ‘Sweet Sue,’ ‘Harbelle,’ ‘Starfire,’ or‘Frost.’ In additional examples, the fruit tree is a nectarine (Prunuspersica var. nucipersica) cultivar, such as ‘Hardired,’ ‘August Red,’‘September Red,’ ‘Spring Bright,’ ‘Summer Fire,’ ‘Early Diamond,’‘Spring Diamond,’ ‘Red Diamond,’ ‘Big Juan,’ ‘Early May,’ ‘May Grand,’‘Arctic Snow,’ or ‘Arctic Glow.’ In other examples, the fruit tree is anapricot (Prunus armeniaca) cultivar, such as ‘Puget Gold,’ ‘Harglow,’‘Westley,’ ‘Goldrich,’ ‘Goldbar,’ ‘Goldstrike,’ ‘Hargrand,’‘Pui-Sha-Sin,’ ‘Reliable,’ ‘Skaha,’ ‘Sundrop,’ ‘Tilton,’ ‘Tomcat,’ or‘Wenatchee.’ One of skill in the art can identify other suitable stonefruit species or cultivars or strains thereof for use in the methodsdisclosed herein.

In other embodiments, the fruit tree is a pone fruit tree, including,but not limited to apple (e.g., Malus domestica), pear (e.g., Pyruscommunis or Pyrus pyrifolia), quince (e.g., Cydonia oblonga), or loquat(e.g., Eriobotrya japonica) tree. In some examples, the fruit tree is anapple (Malus domestica) cultivar, such as ‘Fuji,’ ‘Red Delicious,’‘Golden Delicious,’ ‘Gala,’ ‘Honeycrisp,’ ‘Jonagold,’ ‘Jonathan,’‘MacIntosh,’ ‘Empire,’ ‘Cortland,’ ‘Braeburn,’ ‘Gravenstein,’ ‘Baldwin,’‘Newtown Pippn,’ ‘Granny Smith,’ ‘Cripps Pink,’ ‘Cameo,’ ‘Rome,’‘Winesap,’ ‘Ginger Gold,’ or strains thereof. In other examples, thefruit tree is a pear (Pyrus communis) cultivar, such as ‘Anjou,’ ‘Bosc,’‘Bartlett,’ ‘Cornice,’ ‘Seckel,’ ‘Concorde,’ or ‘Conference.’ In otherexamples, the fruit tree is an Asian pear (Pyrus pyrifolia) cultivar,such as ‘Hamese,’ ‘Shinseiki,’ ‘Kosui,’ ‘Mishirasu,’ ‘Chojuro,’ or‘Atago.’ In some examples, the fruit tree is a quince (Cydonia oblonga)cultivar, such as ‘Champion,’ ‘Smyrna,’ ‘Aromatnaya,’ ‘Carps SweetQuince,’ ‘Cathay Quince,’ ‘Orange,’ or ‘Portugal.’ In further examples,the fruit tree is a loquat (Eriobotrya japonica) cultivar, such as‘Advance,’ ‘Champagne,’ ‘Premier,’ ‘Victor,’ ‘Early Red,’ or ‘Tanaka.’One of skill in the art can identify other suitable pone species orcultivars or strains thereof for use in the methods disclosed herein.

VI. Formulations and Methods of Application

The methods disclosed herein utilize compositions which include BABA,PCa, gibberellins, and/or CPA. Compositions including these compoundscan be formulated using routine methods in the art. For example, thecompounds can be formulated with agriculturally acceptable carriers ordiluents. Agriculturally acceptable carriers include adjuvants, mixers,enhancers, or combinations thereof suitable for application of thecomposition. Examples of suitable liquid agriculturally acceptablecarriers include water, toluene, xylene, petroleum naphtha, crop oil,acetone, methyl ethyl ketone, cyclohexanone, trichloroethylene,perchloroethylene, ethyl acetate, amyl acetate, butyl acetate, propyleneglycol monomethyl ether and diethylene glycol monomethyl ether,methanol, ethanol, isopropanol, amyl alcohol, ethylene glycol, propyleneglycol, and glycerine. Exemplary solid agriculturally acceptablecarriers include talc, pyrophyllite clay, silica, attapulgus clay,kieselguhr, chalk, diatomaceous earth, lime, calcium carbonate,bentonite clay, Fuller's earth, cotton seed hulls, wheat flour, soybeanflour, pumice, wood flour, walnut shell flour, and lignin. Additionaladjuvants include antifoam agents, neutralizing agents, buffers,dispersing agents, thickening agents, sequestering agents, and so on.

The compositions may include one or more compounds in the form of anagriculturally acceptable salt. Agriculturally acceptable salts includesalts, the cations or anions of which are known and accepted in the artfor the formation of salts for agricultural or horticultural use.Preferably the salts are water-soluble. Suitable salts with basesinclude alkali metal (such as sodium and potassium), alkaline earthmetal (such as calcium and magnesium), ammonium and amine (for example,diethanolamine, triethanolamine, octylamine, morpholine anddioctylmethylamine) salts. Suitable acid addition salts include saltswith inorganic acids, for example hydrochlorides, sulfates, phosphatesand nitrates and salts with organic acids, for example acetic acid.

In some examples, the concentration of the active ingredients in thecomposition (for example, BABA, PCa, GA, CPA, or a combination thereof)is about 0.001 to about 98% by weight (for example, about 0.01 to 90% byweight). In compositions designed to be employed as concentrates, theactive ingredient is generally present in a concentration from about 5to about 98 weight %, such as, but not limited to about 10 to 90 weight%. Such compositions can be diluted with a carrier, such as water,before application

Particular formulations to be applied in spraying forms, such as waterdispersible concentrates or wettable powders, may contain surfactants,such as wetting and dispersing agents, e.g., the condensation product offormaldehyde with naphthalene sulfonate, an alkyl-aryl-sulfonate, alignin sulfonate, a fatty alkyl sulfate, an ethoxylated alkylphenol oran ethoxylated fatty alcohol.

In some examples, the compounds included in the compositions disclosedherein are in either solid or liquid application forms, such as in theform of a wettable powder, an emulsion concentrate, a water dispersiblesuspension concentrate (“flowable”), a dusting powder, a granulate, adelayed release form incorporating conventional carriers, diluentsand/or adjuvants. Such compositions may be produced in any conventionalmanner, for example, by mixing the active ingredient with a carrier andother formulating ingredients.

In further examples, the compositions disclosed herein also include oneor more other agents useful in fruit production, for example, one ormore fungicide, herbicide, pesticide, or a combination of two or morethereof. The compositions can also be applied in combination with one ormore other agents useful in fruit production for example, one or morefungicide, herbicide, pesticide, or a combination of two or morethereof. The term “application in combination” or “co-application”refers to both concurrent and sequential application of the activeagents.

The following examples are provided to illustrate certain particularfeatures and/or embodiments. These examples should not be construed tolimit the invention to the particular features or embodiments described.

EXAMPLES Example 1 Decreasing Cold Damage in Tree Fruit

This example describes frost protection in tree fruit utilizingDL-β-aminobutyric acid (BABA).

Sweet cherry cv. ‘Bing’ trees were sprayed in the field with BABA andthe fate of flowers from randomly selected sample limbs placed in aprogrammable freeze chamber was evaluated. Random limbs were removedfrom the freeze chamber within 10 minutes of reaching selected airtemperatures, and were left at room temperature for 1 hour. Pistil/ovarysurvival was then assessed visually on every flower. Flowers withhealthy green stylar and ovary tissue were rated as live. Flowers withdiscolored (for example, brown) stylar or ovary tissues were rated asdead. Fruit set, fruit size, average leaf area, and leaf chlorophyllcontent index were evaluated on other limbs of the treated trees.

Treatment with 100 ppm BABA decreased the percentage of flowers killedat both −3.5° C. and −4.5° C. as compared to control (untreated) trees(FIG. 1A). Treatment with 500 ppm BABA also decreased the percentage offlowers killed (FIG. 1A). Treatment with BABA at both concentrationsalso increased fruit set, fruit size, average leaf area, and leafchlorophyll content index as compared to control (FIGS. 1B-E).

BABA was also applied to ‘Fuji’ apple trees at different bud developmentstages. Five days later, treated and untreated (control) branches werecollected and placed in a programmable freeze chamber. Flowers killedwere evaluated as described above. BABA decreased the percentage offlowers killed as compared to control at all developmental stages,except for full opened flowers (FIG. 2).

Application of BABA to sweet cherry cultivars ‘Bing,’ ‘Chelan,’ and‘Van’ in autumn decreased the percentage of flowers killed after naturalfrost damage the following spring (FIG. 3). Autumn application of BABAalso increased pistil survival in sweet cherry cv. Bing after springfrost damage (FIG. 4).

Finally, BABA application in the spring 4-7 days prior to frost exposureincreased fruit set in plum cv. ‘PP7524-7’ following spring frost damage(FIG. 5).

Example 2 Increasing Fruit Size and Fruit Quality in Tree Fruit

This example describes increasing fruit size, fruit yield, and fruitquality in tree fruit utilizing prohexadione-calcium (PCa) alone or incombination with gibberellins.

Materials and Methods

A limb trial was conducted to evaluate effects of bioactive gibberellins(GA), prohexadione-calcium (PCa), or combinations applied before harveston fruit quality of sweet cherry. The most efficacious treatments wereutilized in a larger scale trial to investigate their effects on thewhole tree scale and postharvest characteristics of fruit.Twelve-year-old sweet cherry cv ‘Bing’ on ‘Gisela® 1’ rootstock wasselected for both experiments and trained to a central leaderarchitecture. Both trials were carried out at Washington StateUniversity Roza farm, Prosser, Wash., USA (N 46.2°, W 119.7°).

Experiment 1. Three limbs with uniform vigor were selected from each of10 trees. Treatments were applied to the limbs randomly spread acrossten trees at 30 days after anthesis, approximately coinciding with theonset of pit hardening (stage II of fruit development) in ‘Bing’. Theexperiment consisted of 10 treatments, including water (the untreatedcontrol) and PCa at 150 mg/L. Bioactive GA₁, GA₃, and GA_(4/7) (70:30GA₄:GA₇) were applied as a foliar spray at 30 mg/L alone or incombination with PCa at 150 mg/L. In addition, the combination of GA₃and GA_(4/7) at 30 mg/L was applied, or in combination with PCa at 150mg/L. PCa was the commercial product Apogee® (27.5% PCa; BASF Corp.,Research Triangle Park, N.C.) and all bioactive GAs (purity >90%) werepurchased from OlChemlm Ltd. (Olomouc, Czech Republic). Each treatmentwas made with a pressurized handgun sprayer to entire limbs, ceasing atthe first runoff.

Twenty fruit per treatment were randomly selected and flagged formonitoring fruit growth by measuring fruit equatorial diameter andheight weekly after treatment. All current-season shoots on treatedlimbs were measured weekly to investigate treatment effects on shootgrowth. Harvest timing was determined as the day when the majority offruit had achieved commercial maturity, based on exocarp color. Atharvest, all fruit on treated limbs were harvested and transported tothe laboratory for fruit quality analysis. Floral bud density on thetreated limbs was assessed by counting all spurs and the number ofreproductive buds per spur.

Experiment 2. Experiment 2 included treatments at the whole tree level.Applications of GA₃ or GA_(4/7) (70:30 GA₄:GA₇) were made to entiretrees at 30 mg/L in combination with PCa at 150 mg/L. PCa (150 mg/L)alone was also applied and an untreated control treatment was included.To investigate the role of application timing of plant growthregulators, all treatments were applied at 30 (first spray (FS)) or 37days after anthesis (second spray (SS)). In this experiment, 24 trees inthe same orchard as those in Experiment 1 were selected for whole treetreatment and assigned randomly into one of two 12-tree groups for thetiming study. Treatments were then randomly assigned to each of threetrees per application timing. Treatments were applied to entire trees bypressurized handgun sprayer to the point of first runoff. Allapplications were completed in the morning between 0800 and 1100, andapplied on days with little or no wind. To prevent spray drift ontoneighboring experimental units, all the trees were selected in the samerow and 2-3 trees were selected as ‘border’ trees between experimentalunits.

Twenty fruit per treatment were marked for weekly fruit sizemeasurement, and six current terminal shoots were selected formonitoring shoot growth weekly after treatment. The fruit were harvestedfor crop yield evaluation 42 days after FS (35 days after SS) as thecontrol fruit reached commercial maturity color. Whole tree yield wasdetermined at harvest, in the field, with a portable digital scale. Theeffect of treatment on total yield per tree (kg tree⁻¹) and the yield oflarge fruit (29.8 mm+) (kg tree⁻¹) was assessed. Three sub-samplesconsisting of 250-300 fruits from each tree were sampled for furtherfruit quality analysis, storability evaluation and sensory qualitystudy.

Fruit quality analysis. All fruit from each limb in Experiment 1 andsub-samples from Experiment 2 were weighed individually and fruit sizedistribution was calculated according to fruit weight. Color sorting wasconducted manually according to the color comparators developed by CTIFL(Centre Technique Interprofessionnel des Fruit et Legumes, France),which categorize cherry color into 8 levels from Green, CTIFL 1 to CTIFL7. Fruit number in each category was counted and color distribution wasassessed. Subsequently, all fruit were analyzed for firmness and rowsize measurement with a FirmTech 2 (BioWorks, Inc, Wamego, Kans.) atroom temperature. Then, 25 fruit were randomly selected and 5 groups of5 fruit were mixed for soluble solids content, pH and titratable aciditymeasurement. Fruit soluble solids were measured using a digitalrefractometer (Atago, Japan). Approximately 0.5 mL of juice was droppeddirectly onto the surface of the refractometer and the measurementimmediately taken. Juice pH and titratable acidity were measured with aMettler DL12 Titrator (Mettler-Toledo, Columbus, Ohio).

Storability evaluation. To assess relative differences in shelf lifeamong treatments in Experiment 2, 100 randomly selected fruit wereplaced in paper bags and kept in refrigerated (4° C.) storage afterfruit quality analyses. The fruit were removed after 30 days for qualityevaluation. Each fruit was examined and categorized into one of 4groups, according to the degree of decay and pitting on fruit surface:healthy and free of defects (0); partly decay or pitting (1); around 50%decay or pitting (2); and more than 50% decay or pitting (3). The fruitin each category were counted and the percentage of each category wascalculated. The pedicel status was also investigated and the fruit withcommercial (green color, turgid) pedicels were counted for eachtreatment. Furthermore, fruit from category 0 and 1 were subjected tofirmness testing, as above. Finally, the fruit in category 0 were usedfor sensory taste study.

Sensory analysis. A study of the effects of the application of plantgrowth regulators on fruit sensory taste quality after 30 days ofstorage at 4° C. was conducted. Ten individuals assessed sensoryattributes of the stored fruit. Each panelist was presented with 16fruit (8 cups of two fruit each). Each cup contained two fruit from thesame treatment and the treatments were sampled by each panelist induplicate. Cups were labeled 1 through 8 and each treatment was randomlyassigned to two cups for each panelist. The sensory attributes evaluatedby panelists included overall appearance, firmness, sweetness, tartness,cherry flavor, and overall acceptance. Results were expressed on arelative scale from 0 to 10, where 0 represents the worst and 10represents the best.

Statistical analysis. All trials were established as randomizedcomplete-block designs. All data were subjected to analysis of varianceusing the General Linear Models (GLM) program of the SAS statisticalanalysis package (SAS Institute, Cary, N.C.). Duncan's new multiplerange test was used to compare treatments when ANOVA showed significantdifferences between means.

Results Experiment 1

In the limb trial, single applications of various GAs (30 mg/L) alone at30 days after anthesis (early stage II of fruit development, about 17days before standard GA application timing) did not increase fruitweight compared with the untreated control (Table 1). However, fruitfrom limbs treated with GA₃ plus GA_(4/7) were 10% heavier than thosefrom untreated limbs. PCa (150 mg/L) alone had no positive effect onfruit size.

TABLE 1 Effect of PCa and GAs alone or in combination applied at 30 daysafter anthesis of ‘Bing’ sweet cherry. Fruit weight Fruit diameterFirmness TSS Treatment (g) (mm) (g/mm) (Brix) Control 8.17^(cd)26.13^(cd) 249.4^(e) 17.50^(ef) PCa 7.26^(f) 24.75^(f) 278.3^(c)19.18^(cd) GA₁ 8.44^(bc) 26.52^(bc) 280.2^(c) 20.84^(b) GA₃ 8.23^(cd)26.49^(bc) 316.9^(a) 22.23^(a) GA_(4/7) 8.08^(d) 26.06^(d) 262.9^(d)18.64^(cd) GA₃ + GA_(4/7) 8.75^(ab) 26.94^(a) 278.5^(c) 18.73^(cd) PCa +GA₁ 7.69^(e) 25.62^(e) 302.7^(b) 17.45^(f) PCa + GA₃ 8.76^(a) 26.65^(ab)281.2^(c) 18.59^(cde) PCa + GA_(4/7) 8.98^(a) 26.98^(a) 284.2^(c)18.46^(def) PCa + GA₃ + GA_(4/7) 8.43^(c) 26.41^(bcd) 279.7^(c)19.62^(c) Means followed by a similar letter are not significantlydifferent.

The combinations of PCa+GA₃ and PCa+GA_(4/7) improved fruit weight byabout 15%. Further, the percent of fruit ≧9 g from these PCa+GAtreatments was about 45% as compared to only 20% of the same size fruitin the untreated control (FIG. 6). These combinations also improvedfruit firmness from 245 g/mm in untreated control to 280 g/mm (Table 1).All treatments improved fruit firmness, though GA_(4/7) was the leasteffective. A single application of GAs improved fruit soluble solids.This effect was tempered when GA was combined with PCa (Table 1). Fruitexocarp color development was delayed when GAs were combined with PCa(FIG. 7).

A single application of PCa effectively reduced vegetative vigor;current season extension shoots were less than half the length ofuntreated extension shoots after terminal bud set (FIG. 8).Investigation of flower density revealed no inhibitory effect of anytreatment on return bloom.

Experiment 2

Whole-tree applications of PCa+GA₃ at 30 (FS, first spray) or 37 (SS,second spray) days after anthesis significantly increased ‘Bing’ fruitequatorial diameter and height (FIG. 9). Further, these treatments alsoincreased individual fruit weight by about 20% compared to untreatedcontrol (FIG. 10). In contrast, whole-tree applications of PCa+GA_(4/7)did not improve fruit quality similarly. A further analysis of fruitweight distribution showed that, although both first and second spray ofPCa+GA_(4/7) resulted in 35-40% fruit in ≧10 g category compared withonly 20% in the control, PCa+GA₃ had a significantly greater proportion,with 80% in this category, irrespective of application timing (FIG. 11).In addition, both first and second spray timings of PCa alone resultedin 15% increase in fruit in the ≧10 g category compared to the control.Further, a plot of crop yield/tree vs. large fruit (≧10 g) illustratedthat both PCa+GA₃ and PCa+GA_(4/7) treatments improved crop yield andfruit size in sweet cherry cv ‘Bing’ (FIG. 12). In addition, cherrytrees treated with PCa+GA₃ had more marketable yield than those treatedby PCa+GA_(4/7) in both spray dates in this study (FIGS. 10 and 12).

Whole tree applications of GA₃ or GA_(4/7) plus PCa had a tendency todecrease total soluble solids levels, though this effect was notstatistically significant (FIG. 10). Both single applications of PCa+GA₃improved fruit firmness. Further, these treatments yielded fruit with40% greater firmness than those of the untreated control (FIG. 10). Noother treatment improved fruit firmness. Both PCa+GA₃ and PCa+GA_(4/7)treatments delayed fruit color development and, the former induced ahigher proportion of light color fruit than the latter, irrespective oftiming of application (FIG. 13). Moreover, the second application timinginduced greater delays of color development for both PCa plus GA₃ andPCa plus GA_(4/7).

Current shoot growth showed a different pattern between the two spraydates. No differences in shoot growth among treatments were recordedduring the two weeks following application (FIG. 14). Three weeks afterapplication, shoots in PCa+GA₃ and PCa+GA_(4/7)-treated trees exhibitedhigher rates of growth than the control and PCa treatment (FIG. 14).PCa+GA₃-treated trees also showed a higher shoot length than othertreatments. Irrespective of timing, a single spray of PCa reduced shootgrowth compared with the control and PCa+GAs.

An investigation of fruit storability showed that both preharvestPCa+GA₃ and PCa+GA_(4/7) treatments improved fruit storability (FIG.15). After 30 days in storage at 4° C., only 5% fruit from untreatedtrees were categorized as healthy (free from decay, pitting, visualdefects) and fewer than 10% of PCa-treated fruit were in the samecategory. In contrast, fruit treated with PCa+GA₃ were 46% and 30%healthy in response to FS and SS, respectively. Further, nearly 90% offruit treated with PCa+GA₃ were rated marketable (category 0 and 1).Treatment with PCa+GA_(4/7) at both timings also improved fruitstorability compared to untreated fruit, though not as effectively asPCa+GA₃. The percentage of fruit with green and turgid pedicels afterstorage was highest from the PCa+GA₃ treatment for both FS and SS(>80%). This compared with 55%, 24%, and 30% of similar quality pedicelsfrom first spray treatments of PCa+GA_(4/7), PCa, and the control,respectively (FIG. 16). Moreover, earlier sprays of PCa+GA₃ orPCa+GA_(4/7) before harvest had more beneficial effects on fruitstorability. Further, fruit firmness evaluations showed that PCa+GA₃treated cherries were significantly firmer than those in othertreatments, and these can be evidenced by the difference of fruitfirmness from category 0 (healthy) and 1 (partial decay and pitting)between treatments (FIG. 16).

To investigate whether the stored cherries could meet consumers' sensorypreference, a study of sensory taste quality was conducted followingstorage. Fruit treated with PCa+GA₃ from both spray timings received thehighest scores from all subjects according to the response of the cherrycrew, including sweetness, tartness, cherry flavor, appearance, andoverall acceptance. Fruit treated with PCa+GA₃ showed firmer, sweeter,more cherry flavor intensity than those treated by other treatments.

PCa is an inhibitor of GA biosynthesis and can control vegetativeextension growth in apple and sweet cherry (Elfving et al., Acta Hort.667:439-446, 2005). The competition between vegetative and reproductivesinks has been demonstrated in sweet cherry (Whiting and Lang, J. Am.Soc. Hort. Sci. 129:407-415, 2004). In the experiments described in thisExample, reductions in vegetative extension growth were observed withPCa treatments, in particular at about 2 weeks after first spray.Without being bound by theory, it is believed that reductions invegetative sink activity from applications of PCa favor assimilatepartitioning to cherry fruit growth.

Further, PCa is structurally similar to 2-oxoglutaric acid. This enablesthe compound to inhibit 2-oxoglutarate-dependent dioxygenases, which areinvolved in the formation of growth active gibberellins and in flavonoidmetabolism (Rademacher, Ann. Rev. Plant Physiol. Plant Mol. Biol.51:510-531, 2000). Gibberellic acid biosynthetic pathways are ofconsiderable complexity in plants (Plant Hormones: Biosynthesis, SignalTransduction, Action! Davies (ed.), Kluwer Academic Publishers, 2004).They are divided into an early nonhydroxylation pathway, in which GA₄ isproduced, and an early 13-hydroxylation pathway, in which GA₁ and GA₃are produced (FIG. 17). The points of inhibition in thegibberellin-biosynthetic pathway by PCa include the 3β-hydroxylationpathway, thereby inhibiting the formation of highly active GA₁ and GA₄from inactive precursors (Rademacher, Ann. Rev. Plant Physiol. PlantMol. Biol. 51:510-531, 2000; Hedden and Kamiya, Ann. Rev. Plant Physiol.Plant Mol. Biol. 48:431-460, 1997). In some reports, PCa, paradoxically,leads to increases in shoot growth, most likely by protecting endogenousactive GAs from being metabolically inactivated (Hisamatsu et al., J.Jpn. Soc. Hort. Sci. 67:537-543, 1998). The inactivation of exogenouslyapplied GA₃ and GA₄ by 2β-hydroxylation can be inhibited by simultaneoustreatment with PCa, resulting in increased GA-like activity (Nakayama etal., Plant Cell Physiol. 31:195-200, 1990; Nes and Venkatramesh, Crit.Rev. Biochem. Mol. Biol. 32:81-93, 1999). Without being bound by theory,it is believed that applications of PCa plus GA₃ or GA_(4/7) increasethe concentration of GA_(4/7) and GA₃ in fruit mesocarp tissue, whichpromotes cell enlargement, a critical component of final fruit size insweet cherry (Olmstead et al., J. Am. Soc. Hort. Sci. 132:697-703,2007).

Example 3 Increasing Fruit Set and Fruit Size in Tree Fruit

This example describes increasing fruit set and fruit size in tree fruitutilizing 4-chlorophenoxyacetic acid.

Plant growth regulators were applied to limbs of sweet cherry cv. ‘Bing’at full bloom when essentially all flowers were open. Fruit set wasrecorded as a percent of available flowers from flower counts made priorto application and fruit counts made just prior to harvest. Fruit set intrees treated with 4-chlorophenoxyacetic acid (CPA) at 10 or 30 ppm washigher than untreated control in both small and large scale trials (FIG.18). Fruit set and fruit size at harvest were also increased incultivars ‘Bing,’ ‘Tieton,’ and ‘8011-3’ treated with 30 ppm CPA appliedto the flowers at full bloom. (Table 2).

TABLE 2 Fruit set and fruit size at harvest Fruit Set (%) Average fruitsize (g) Cultivar 4-CPA Untreated 4-CPA Untreated Bing 58.0 30.0 8.4 7.3Tieton 35.0 26.0 8.6 7.2 8011-3 16.0 7.0 13.6 10.5

In view of the many possible embodiments to which the principles of thedisclosure may be applied, it should be recognized that the illustratedembodiments are only examples and should not be taken as limiting thescope of the invention. Rather, the scope of the invention is defined bythe following claims. We therefore claim as our invention all thatconies within the scope and spirit of these claims.

1.-8. (canceled)
 9. A method of increasing fruit size or fruit qualityof fruit from a fruit tree, comprising applying to the fruit tree afteranthesis an effective amount of a composition comprisingprohexadione-calcium, thereby increasing fruit size or fruit quality offruit from the tree as compared to a control.
 10. The method of claim 9,wherein the composition is applied to the fruit tree leaves, buds,flowers, branches, or a combination of two or more thereof.
 11. Themethod of claim 9, wherein the composition comprisingprohexadione—calcium is applied between about 25 to 40 days afteranthesis.
 12. The method of claim 9, wherein the composition comprisingprohexadione—calcium comprises about 100 to 200 mg/Lprohexadione-calcium.
 13. The method of claim 9, wherein the compositioncomprising prohexadione—calcium further comprises one or moregibberellins.
 14. The method of claim 13, wherein the one or moregibberellins comprises gibberellin A1, gibberellin A3, gibberellin A4,gibberellin A7, or a combination of two or more thereof.
 15. The methodof claim 13, wherein the composition comprising prohexadione-calcium andthe gibberellin is applied between about 25 to 40 days after anthesis.16. The method of claim 13, wherein the composition comprisingprohexadione—calcium and gibberellin comprises about 100-200 mg/Lprohexadione-calcium.
 17. The method of claim 13, wherein thecomposition comprising prohexadione—calcium and gibberellin comprisesabout 20-40 mg/mL gibberellin 3 or about 20-40 mg/mL gibberellin 4/7.18. The method of claim 9, wherein the fruit tree is a stone fruit tree.19. The method of claim 18, wherein the stone fruit tree is selectedfrom the group consisting of sweet cherry, tart cherry, plum, peach,nectarine, and apricot.
 20. The method of claim 9, wherein increasingfruit size comprises increasing fruit weight, fruit diameter, fruitlength, fruit width, or a combination of two or more thereof as comparedto the control.
 21. The method of claim 9, wherein increasing fruitquality comprises increasing fruit firmness, fruit total soluble solidcontent, fruit color, fruit storability, fruit sensory attributes, or acombination of two or more thereof as compared to the control.
 22. Amethod of increasing fruit size of fruit from a fruit tree comprisingapplying to the fruit tree an effective amount of a compositioncomprising 4-chlorophenoxyacetic acid, thereby increasing fruit size ascompared to a control.
 23. The method of claim 22, wherein thecomposition is applied to the fruit tree leaves, buds, flowers,branches, or a combination of two or more thereof.
 24. The method ofclaim 22, wherein the composition comprising 4-chlorophenoxyacetic acidis applied during flowering.
 25. The method of claim 22, wherein thecomposition comprising 4-chlorophenoxyacetic acid comprises about 10 to100 mg/L 4-chlorophenoxyacetic acid.
 26. The method of claim 22, whereinthe fruit tree is a stone fruit tree.
 27. The method of claim 26,wherein the stone fruit tree is selected from the group consisting ofsweet cherry, tart cherry, plum, peach, nectarine, and apricot.
 28. Themethod of claim 22, wherein increasing fruit size comprises increasingfruit weight, fruit diameter, or fruit length as compared to thecontrol.
 29. A method of increasing fruit set of a fruit tree comprisingapplying to the fruit tree an effective amount of a compositioncomprising 4-chlorophenoxyacetic acid, thereby increasing fruit set ofthe fruit tree as compared to a control.
 30. The method of claim 29,wherein the composition is applied to the fruit tree leaves, buds,flowers, branches, or a combination of two or more thereof.
 31. Themethod of claim 29, wherein the composition comprising4-chlorophenoxyacetic acid is applied during flowering.
 32. The methodof claim 29, wherein the composition comprising 4-chlorophenoxyaceticacid comprises about 10 to 100 mg/L 4-chlorophenoxyacetic acid.
 33. Themethod of claim 29, wherein the fruit tree is a stone fruit tree. 34.The method of claim 33, wherein the stone fruit tree is selected fromthe group consisting of sweet cherry, tart cherry, plum, peach,nectarine, and apricot.
 35. The method of claim 29, wherein increasingfruit set comprises increasing the percentage of flowers that developinto fruit as compared to the control.